Defined in 3 files as a macro:

• include/uapi/linux/tcp.h, line 148 (as a macro)
• tools/include/uapi/linux/tcp.h, line 135 (as a macro)
• tools/testing/selftests/bpf/prog_tests/sockmap_basic.c, line 24 (as a macro)

Referenced in 4 files:

• net/ipv4/tcp.c, line 3994
• tools/testing/selftests/bpf/prog_tests/sockmap_basic.c, line 58
• tools/testing/selftests/net/tcp_ao/icmps-discard.c, line 356
• tools/testing/selftests/net/tcp_ao/lib/repair.c, line 244